Chemical processes and products



Patented June 2s, 194e' 2,402.698

UNITED 7 STATES PATENT v OFFICE James B. Wei-nu, wummmh, DeL, assirnor to E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application Apr-i123, 1942,

Serial No. 440,249

1- v12 Clalms." (c1. zoo-e09) 2 This invention relates to a catalytic process and catalyst, and refined by fractional distillation or products therefrom and more particularly it reby any other appropriate method. According to lates to a process for the production oi cyclic this process, sulfurized cyclic terpenecompounds thiols and productstherefrom. are converted smoothly in good yields to thiols.

a new and improved method for the preparation from cyclic terpene compounds. Another object for the production of thiols from cyclic terpene compounds, said process using readily available This invention has as its object the preparation 5 In the following examples the parts are given of certain new products derived from cyclic'terby weight.

pene compounds. Another object is to provide Example I Seventeen hundred fifty-six parts of alphapinene and 400 parts of sulfur are heated in an autoclave at 150 C. for 8 hours under autogenous pressure. The reaction mixture is cooled to room temperature and '75 parts of finely divided, reis to provide a prooess.for the production of duced nickel catalyst is added. The mixture is thiols from cyclic terpene compounds in high 15 then hydrogenated at 1500' and 600 to 700 v fl pounds per square inch. Under these conditions yields Stu] another Object is toprovideapmcess the reaction usually requires 8 to 9 hours, and

" the mixture is heated at 150 C. for l to 2 hours of thiols derived from cyclic tezpene compounds which process utilizes low-cost raw materials. 10 Still another object is to provide a commercially practical process for the production 01' thiols rawvmatefla1s other objects will be apparent after the last pressure drop to insure a complete ing invention which comprises catalytically hyreaction. After cooling to room temperature, the catalyst is removed by filtration and the crude thiol derived from pinene fractionally distilled at 25 mm. pressure to obtain essentially pure fmgenatmg summed cyclic terpene thiol. The product Iboils at 114.5 to 114.6 0., re- 1n the presence of a sulfactive hydrogenation '26 catalyst. This reaction may be carried out in active mdex 15024 total and either the liquid or vapor phase and under a capta'n sulfur found 8' This distill, superatmospheric pressure and temperature, tend 001mg to 2% hows yields preferably at a pressure of at least atmospheres large wmte crystals melting at 55 and liquid $2.? 33 ;338: 8 within. the range of about so liquid fraction show strong absorption bands at The exact manner of practicing this invention 8 of 14 00; 12 65; 1 1.55; ll.3(l; ll.0il5 Wm vary with the particular compounds WW 10.65, 10.45, ions, can, ace, 9.sc, 9.1o, s.cc, essed; however, the following will illustrate its 8'75; 8'40; and

from the following description of the invention.

These objects are accomplished by the followresidue. Both the crystalline mercaptan and the application: 100 parts of a sulfurlzed cyclic termicrons when examined by mfl'ared light we compound either alone or dissolved in a in accordance with the method used for detersuitable solvent, is mixed with 3 to 15 parts of a, mining infrared absm'ptmn as described m Emmet, h are enauon cam t of the re article by W. H. Avery, entitled, Infrared specfesentediyiobfit and nickel g fig g trometer for industrial use, which appears in the t a mghpressure reaction vessel equipped t J. Optical 800. Am. 31, 633-638 (1941) an inlet for hydrogen and an efllcient device for 40 Example II agitation. Hydrogen under pressure is admitted to th vessel the pressure B above sevfinteen hundred fifty-Six part8 Qf beta out atmospheres and preferably the plnelle and parts of Sulfur are heated in an neighborhood of about 50 atmospheres, and the autoclave at 150 C. for 8 hours under autogenous mixtureis h ated to b t about '75 Q and pressure. The reaction mixture is cooled to room 300 c, and generally between about 00 Q and temperature and '75 parts of reduced nickel cata- 200 C. Under these conditions hydrogen i lyst supported on kieseiguhr areadded. The mixsorbed smoothly and, if necessary, additi l ture is then hydrogenated at 150 C. and 600 to amounts ar added from time to ti to-maim- 700 pounds per square inch. This reaction usual= r t pressure within a suitable working rams ly requires 8 to 9 hours, and the mixture is heated The absorption of hydrogen is usually complete at C. for l to 2 hours after the last pressure within 2 to' 5 hours. The reaction vessel is cooled d op to insure a complete rea After 6 to room temperature. purged to eliminate the in to r om te p th t ly i m d hydrogen sulfide produced in the reaction, and by filtration and the crude thiol derived from the product is removed, filtered-to separate the 66 beta-pinene fractionally distilled at 25 mm. pressure to obtain essentially pure thiol. 'uct boils at 111 to 113 C.; refractive index 11 1.5044; sulfur found 18.85%.

- ing terplnolene in place of dipentene. The thiol The prod- Example III Seventeen hundred fifty-six parts of dipentene 5 4 and 400 parts of sulfur are heated in an autoclave at 150 C. for 8 hours under autogenous pressure. The reaction mixture is cooled to room Y temperature and '75 parts of finely divided, re- 10 at 150 C. for 1 to 2 hours after the last pressure drop to insure a complete reaction. After cooling to room temperature the catalyst is removed by filtration and the crude thiol fractionally distilled at 25 'mm. pressure to obtain essentially pure mercaptan and a higher boiling derivative containing two sulfur atoms, but only one mercaptan group per molecule. Boiling range of thiol 118 .to 119 C.; refractive index 11. 1.5188; sulfur found 18.96%. Boiling range of the higher boiling derivative 152 to 162 C.; refractive index 11 1.5459; sulfur found 30.34%.

Example IV A thiol derived from terpinolene is prepared in a manner similar to Example 111 but employderived from terpinolene has the following physical characteristics: Boiling range 137 to 138 0.; refractive index n 1.5340; sulfur found 19.08%.

Example V 4 A thiol derived from menthene is prepared in a manner similar to Example '111 but employing menthene in place of dlpentene. The thiol has the following physical characteristics: Boiling range 116 to 122 0.; refractive index 11 1.4894; sulfur found 18.48%.

Example VI .A thiol derived from alpha-terpineol' is prepared in a manner similar to Example 111 but employing alpha-terpineol place of dipentene. The thiol derived from alpha-terpineol has the following physical characteristics: Boiling range 140 to 146 C.; refractive index n 1.5176; sul- 5o fur found 18.12%.

7 Example VII Five hundred forty-seven parts of camphene and 249 parts of sulfur are heated ina steel autoclave provided with agitation at 150 0. for

10 hours under autogenous pressure. The condensation mixture is cooled to room temperature and 40 parts of reduced nickel catalyst is added. The mixture then is hydrogenated at 150 C. and

600 to 700 pounds per square inch until hydrogen 50 Example VIII '70 Three hundred parts of verbenone is heated with parts sulfur for 8 hours at to C. and then for 8 hours at C. The sulfurized product is diluted with 500 parts benzene and 25 parts reduced nickel catalyst is added.

until no more pressure drop occurs. rial is filtered from the catalyst and a thiol charge is reduced in an autoclave at 150 C. withhydrogen at 600 to 700 pounds per square inch The matederived. from verbenone recovered.

Example IX One thousand eighty-eight parts of pinene, 246 parts of sulfur, and 55 parts reduced nickel catalyst are charged intoan autoclave and heated for 8 hours at C. Then hydrogen pressure at 500 pounds is placed on the autoclave and the reaction mass reduced until no further pressure drop occurs. This takes approximately 10 hours. The reaction mass is cooled and discharged, much hydrogen sulfide being evolved. The reaction mass isheated to 70 C. under vacuum with nitrogen passing over it until all the hydrogen sulfide is removed. Total weight of crude thiol derived from pinene is 1133 -parts.

' Examlple X Three thousand sixty parts of alpha-pinene and 770 parts of sulfur are charged into a 4.5 liter steel autoclave and the mixture heated to 150 C. The charge is held at 150 C. for 8 hours and then cooled. One hundred fifty parts of a reduced nickel catalyst is added, the autoclave is swept with hydrogen and the charge hydrogenated under pressure of 400 to 500 pounds per square inch of hydrogen at 150 C. until no further pressure decreaseoccurs. The charge is cooled and the catalyst separated from the reaction mixture by filtration. Thirty-two hundred fifty parts of a product analyzing 14.13% ulfur is obtained; this corresponds to a 64% conversion to a thiol derived from pinene.

The temperature of sulfurization may be var: ied within wide limits prescribed by the reactivity and stability of the terpene on which the reaction is being carried'out. Some terpenes are more active than others and will sulfurize at a lower temperature, whereas some sulfurized terpenes are more unstable than others and may not be heated beyond certain decomposition temperatures at which point hydrogen sulfide is evolved. In general, 150 C. has been found to be a satisfactory temperature for sulfurization. Additional details on the sulfurization of unsaturated compounds are disclosed in copending application of J. H. Werntz, Serial No. 392,136, filed May 6, 1941.

The sulfurized terpene compounds used in the practice of this invention are preferably those which are obtained by reacting elemental sulfur with terpene compounds in equimolar proportions. Higher proportions of sulfur to cyclic terpene compounds can be used; for example, ratios as high as 3:1 can be employed.

The temperature of hydrogenation may also be varied depending upon the catalyst employed, the hydrogen pressure, and the reactivity of the sulfurized terpene employed. Higher pressures may be advantageously employed if the equipment used is sufliciently strong. The invention contemplates the hydrogenation of sulfurized terpenes at superatmospheric temperatures and pressures either by batchwise or by continuous flow liquid phase methods. In general, the hydrogenation process of the invention may .be best carried out in the liquid phase at pressures of at least 10 atmospheres and temperature between about 100 C. and 200 C. For batchwise operations it has been found particularly convenient The 75 to employ pressures between about 20 and 300 In the practice of the invention, sulfurized terpene compounds may be hydrogenated either alone or dissolved in suitable solvents. If solvents are employed, inert materials of the type represented by benzene, toluene, xylene, petroleum ether, ligroin, and the like, are especially suitable. Alcohols; ethers, e. g. dioxane and even non-solvents such as water may be used as the reaction medium. It i preferable, however, to avoid the use of solvents. wherever possible in view of the recovery problem and the attendant reduction in space-time yield and equipment efficiency. Additional operating details are disclosed in copending application of W. A. Lazier, Signaigo, and J H. Werntz', Serial No. 411,336, filed September 18, 1941.

In the practice of this invention any sulfactive hydrogenation catalyst may be used. Catalysts suitable for use in the process may be selected from the group of corrosion-resistant sulf-' active materials comprising the sulfides and polysulfides of metals of groups I, VI, and VIII of the periodic table. Typical examples of catalyst compositions that are particularly eflicient are thesulfides of cobalt, nickel, iron, molybdenum, tungsten, and chromium, and of these, the first four mentioned are preferred because of their high activity. These catalysts are conveniently prepared according to the methods described in copending applications of F. K. Signaigo, Serial No. 319,241, filed February 16, 1940, and Serial No. 319,242, filed February 16, 1940, and that of B. W. Howk, SerialNo. 353,936, filed August 23, 1940. For example, efficient catalysts can be produced by precipitation methods in which a soluble salt of a metal such as cobalt is treated in solution with sodium or'ammonium polysulfide. Particularly active catalysts are obtained by treating a pyrophoric hydrogenating metal with a sulfiding agent such as hydrogen sulfide, free sulfur or organic compounds of bivalent sulfur at moderate temperatures. As disclosed in the above examples, the latter process may be carried out conveniently in situ prior to the hydrogenation operation by charging the free metal together with the sulfurized terpene compound. The former will react with some of the sulfurized terpene compound with the formation of a sulfactive metal sulfide catalyst. The selection of a particular catalyst for the hydrogenation of sulfurized terpene compounds will depend principally upon the considerations of temperature and pressure to be employed in the hydrogenation process since some catalysts are active at lower temperatures than others. In general, the catalysts of this invention can be employed in the massive state or deposited on a suitable supporting material such as kieselguhr, pumice or activated charcoal. The catalysts may be used singly or in various combinations. For liquid phase, batch operations it is preferred to use between about 1 and parts of catalyst in the form of finely divided powder for each 100 parts of sulfurized terpene compound. For continuous liquid phase hydrogenation, solid lumps or briquettes of suitable size and capable of withstanding erosion will be found desirable.

The cyclic terpene compounds employed in clude the monocyclic and unsymmetrical bicyclic terpenes or mixtures thereof. In place of the terpenes disclosed in the examples there may also be employed mixtures of terpenes such as are found in pine oils, turpentine, camphor oils, and such oils as are obtained as by-products in commercial processes for making camphor. The cyclic terpene compounds employed in Examples I, II, III, IV,-V, VI, VII, and X had the following physical characteristics: The alpha-pinene had a distillation range between 156.2 C. and 157.7" C. with 90% distilling within th range of 156.3 C. to 157.0" C. It had a refractive index of 11 1.4652 and a" specific gravity 155/155 of 0.8638. The beta-pine'ne had a distilling range of between 163.0 Cband 172.6" C. with 80% distilling between 164.0 and 167.0. This'compound had a refractive index n 1.4750 and a specific.

C. This compound had a refractive index n 1.4728, an iodine number of 258 and a specific gravity 15.5/ 15.5 of 0.8491. The terpinolene had a distilling range between 181.2 Ciand 221.4" C.

with 80% distilling between 182.8"..Q and 193.4 C. This compound had an iodine number of 290.9. The nienthene had a distilling range between 168.5 C. and 174.5" C. with 80% distilling .between 169.1 C. and 170.5 C. This compound had a refractive index n 1.4526 and an iodine numberof of 208. The camphene had a distilling range between 157.3 C. and 160.1 C. with 80% distilling between 158.0 C. and 159.1 C. This compound had a refractive index 12 1.4950, a freezing point of 37.9 C. and a specificgravity 15.5/15.5 of 0.8366.

The thiols derived from the cyclic terpene compounds as obtained by the process of this invention are useful as flotation agents and as organic intermediates having a wide variety of uses in industry.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not to be limited to the specific embodiments shownand described. I a

I claim:

1. The process for the preparation of thiols which comprises catalytically hydrogenating a 'sulfurized cyclic terpene compound in the presence of a sulfactive hydrogenation catalyst.

2. The process for the production of thiols which comprises reacting a sulfurized cyclic terpene compound with hydrogen at a superatmospheric temperature and pressure in the presence of a sulfactive hydrogenation catalyst.

3. The process for the production of thiols which comprises reacting a sulfurized cyclic ter pene compound with hydrogen at a temperature between about C. and about 300 C. in the presence of a suifactive hydrogenation catalyst.

4.. The process in accordance with claim 3 characterized in that the reaction is carried out at a pressure of at least 10 atmospheres.

5. The process which comprises sulfurizing a cyclic terpene compound and then catalytically hydrogenating said sulfurized cyclic terpenc compound in the presence of a sulfactive hydrogenation catalyst.

6. The process for the production of thiols which comprises catalytically hydrogenating in the presence of a sulfactive hydrogenation catalyst a sulturized cyclic terpene compound, said compound having been sulfurized with atv least equimolar proportions of sulfur.

7. The process forthe production of thiols which comp :ycatalytically hydrogenating a suifurized bicyclic 'terpene compound in the presence or a sulfactive hydrogenation catalyst.

8. The process for the production of thiols which comprises, catalyticaily hydrogenating a sulfurized pinene in the presence of a sulfactive hydrogenation catalyst.

9. A thicl derived from a cyclic terpen'e compound characterized in that said thiol is prepared by catalyticaily hydrogenating a sulfurized cyclic terpene compound in the-presence of a. suli active hydrogenation catalyst.

10. A thiol derived from a cyclic terpene compound characterized in that said thiol is prepared by catalytically hydrogenating in the presence of a sulfactive hydrogenation catalyst a sulfurized 8 a cyclic terpene compound, said compound having been sulfurized with at least equimolar proportions of sulfur. 11. A thiol derived from an unsymmetrical bicyclic terpene compound characterized in that it is prepared by catalytically hydrogenating a sulfurized unsymmetrical bicyclic terpene compound in the presence of a sulfactive hydrogenation catalyst.

12. A thiol derived from pinene characterized in that it was strong infrared absorption bands at the following wave lengths expressed in microns: 14.00; 12.65; 11.55; 11.30; 11.00; 10.65; 

